This invention relates to d.c. to d.c. converters and more particularly to a transformer-coupled two-inductor buck converter.
It is highly desirable to provide a d.c. to d.c. buck converter, i.e., a converter capable of simply transforming a d.c. input voltage to a selected lower level d.c. output voltage. Such a converter is important since the input voltage provided by a d.c. source is seldom the correct d.c. voltage level needed to operate a given piece of equipment.
When providing such a buck converter it is desirable to use a topology which inherently provides for both the input and output currents to be continuous. By continuous is meant that the input and output currents have no abrupt changes in level and are never zero in value. Moreover, in many applications, it is desirable to provide such a buck converter which inherently enables even a ripple on the input current to be minimized or even reduced to zero thereby providing a steady d.c. input current. This reducing of abrupt changes and ripple on the input current of a buck converter is especially important because of the need for preventing electromagnetic interference (EMI) effects from being present on other equipment that may be tied into the same supply line from a source of d.c. input voltage.
It is further desirable to provide a buck converter which inherently provides continuous input and output currents wherein the input and output circuits of the buck converter are transformer-coupled so as to isolate the ground return of the source and load since most applications of a buck converter require such isolation.